Is the Fourth Amendment Going to the Dogs?

Most of us know that the Fourth Amendment to the U.S. Constitution protects us from unreasonable searches and seizures.

Usually, cases turn on whether a particular search or seizure is reasonable. But a recent U.S. Supreme Court case raised the thought-provoking question: What is a search?

How would you answer that question? Let's compare your answer to the U.S. Supreme Court decision in Illinois vs. Caballes.

Roy Caballes was stopped for speeding by Illinois State Trooper Daniel Gillette. Caballes was going 71 miles per hour in a 65 mph zone. No big deal so far. Gillette radioed this routine traffic stop in to his dispatcher.

It so happened that another trooper, Craig Graham, who was with the State Police Dog Drug Interdiction Team, heard the radio call. Even though Gillette had not asked for any assistance, Graham decided to go the scene and conduct a canine sniff. By the time Graham arrived with the dog, Gillette had already checked the validity of Caballes' license, registration and proof of insurance and, finding nothing amiss, was in the process of writing Caballes a warning.

If Graham and the dog had not arrived, at that point, Caballes should have been free to drive away. He wasn't under arrest, and the purpose of the stop was over. But Graham walked the dog around the car. The dog "alerted" at the trunk of the car, meaning the dog's conduct indicated it had detected the drugs it had been trained to identify. After opening the trunk, the troopers found a very large stash of marijuana and arrested Caballes. He was charged with trafficking in marijuana.

At trial, Caballes moved to suppress the marijuana as evidence, arguing that it was found as a result of a search that violated the Fourth Amendment.

He conceded that the traffic stop was a proper one. But, he argued, the police had no acceptable reason to search the car. Nothing happened after he was stopped that justified turning a routine traffic stop into a drug investigation. The Illinois Supreme Court agreed with him, but the U.S. Supreme Court did not, reversing the Illinois high court in a 6-2 decision. (Chief Justice William Rehnquist, who is ailing, did not participate in the decision.)

As a general rule, police need some individualized suspicion of wrongdoing to conduct a search and still need probable cause to search a car. Caballes argued that the dog sniff was an unreasonable search because the police had absolutely no reason to suspect him of any wrongdoing. But the court majority threw Caballes a curve. It held that the dog sniff was not a search at all.

So we are back to the question: What is a search? A search involves the government's intrusion into an area where citizens have a reasonable and legitimate expectation of privacy, such as one's house. If you are wondering how much privacy a person can expect in his car, the court didn't look at it that way.

Justice John Paul Stevens, author of the majority opinion, noted that no citizen has any reasonable expectation of privacy in the possession of contraband. The dogs are trained only to alert police to illegal drugs, not to anything a citizen has a right to keep private. So a sniff is not a search.

Because a sniff is not a search, the Fourth Amendment is not implicated. In Justice Stevens' words, "A dog sniff conducted during a concededly lawful traffic stop that reveals no information other than the location of a substance that no individual has any right to possess does not violate the Fourth Amendment."

Justice Ruth Bader Ginsburg, joined by Justice David Souter, dissented. She agreed with the Illinois Supreme Court that any investigation must be "reasonably related in scope" to the circumstances that justified the police interference in the first place and agreed that the state -- which has the burden of proof on this point -- failed to offer adequate justification for the sniff. Whether or not a sniff is a search, she would find that turning a routine traffic stop into a drug investigation, without any reason to suspect wrongdoing, unconstitutionally broadened the scope of the traffic stop.

Justice Souter also wrote his own separate dissent. He would find a dog sniff a search -- and an unreasonable one under the facts of this case.

Whether or not a sniff is a search, it bothers me each time the Supreme Court moves away from requiring individualized suspicion of wrongdoing in citizen encounters with police or other authority.

The court has gone back and forth on this point in recent years, OK-ing random drug tests for students participating in any extracurricular activities and a traffic checkpoint to find information about a hit and run accident but nixing the use by police of a thermal imaging device in a car to detect marijuana growing in a house across the street and a highway checkpoint merely to find evidence of ordinary criminal wrongdoing.

Marianna Brown Bettman, a former Ohio appeals court judge, teaches at the University of Cincinnati College of Law.